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    <title>ShellCheck: SC1076 – Trying to do math? Use e.g. `[ $((i/2+7)) -ge 18 ]`.</title>
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    <h1>SC1076 – ShellCheck Wiki</h1>
    <a href="https://github.com/koalaman/shellcheck/wiki/SC1076">See this page on GitHub</a>
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    <h2 id="trying-to-do-math-use-eg--i27--ge-18-">Trying to do math? Use
e.g. <code>[ $((i/2+7)) -ge 18 ]</code>.</h2>
<h3 id="problematic-code">Problematic code:</h3>
<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="SC1076.html#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="bu">[</span> i / 2 <span class="er">+</span> <span class="ex">7</span> <span class="at">-ge</span> 18 ]</span></code></pre></div>
<h3 id="correct-code">Correct code:</h3>
<div class="sourceCode" id="cb2"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb2-1"><a href="SC1076.html#cb2-1" aria-hidden="true" tabindex="-1"></a><span class="bu">[</span> <span class="va">$((i</span> <span class="op">/</span> <span class="dv">2</span> <span class="op">+</span> <span class="dv">7</span><span class="va">))</span> <span class="ot">-ge</span> 18 <span class="bu">]</span></span></code></pre></div>
<h3 id="rationale">Rationale:</h3>
<p>ShellCheck found a loose <code>+*/%</code> in a test statement. This
usually happens when trying to do arithmetic in a condition, but without
using the arithmetic expansion construct
<code>$((expression))</code>.</p>
<p>In C, <code>if (a+b == c)</code> is perfectly fine, but in sh this
must be written to first expand the arithmetic operation like
<code>if [ $((a+b)) = c ]</code>.</p>
<h3 id="exceptions">Exceptions:</h3>
<p>None.</p>
<h3 id="related-resources">Related resources:</h3>
<ul>
<li>Help by adding links to BashFAQ, StackOverflow, man pages, POSIX,
etc!</li>
</ul>
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    <p style='font-size: 80%'><a href="../index.html">ShellCheck</a> is a static analysis tool for shell scripts. This page is part of its documentation.</p>
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